Frequency of Screening for Weaning From Mechanical Ventilation: Two Contemporaneous Proof-of-Principle Randomized Controlled Trials*

It is unknown whether more frequent screening of invasively ventilated patients, identifies patients earlier for a spontaneous breathing trial, and shortens the duration of ventilation. We assessed the feasibility of conducting a large trial to evaluate screening frequency in critically ill adults in the North American context.We conducted two contemporaneous, multicenter, pilot, randomized controlled trials (the LibeRation from MEchanicaL VEntilAtion and ScrEening Frequency [RELEASE] and Screening Elderly PatieNts For InclusiOn in a Weaning [SENIOR] trials) to address concerns regarding the potential for higher enrollment, fewer adverse events, and better outcomes in younger patients.Ten and 11 ICUs in Canada, respectively.Parallel trials of younger (RELEASE < 65 yr) and older (SENIOR ≥ 65 yr) critically ill adults invasively ventilated for at least 24 hours.Each trial compared once daily screening to "at least twice daily" screening led by respiratory therapists.In both trials, we evaluated recruitment (aim: 1-2 patients/month/ICU) and consent rates, reasons for trial exclusion, protocol adherence (target: ≥ 80%), crossovers (aim: ≤ 10%), and the effect of the alternative screening frequencies on adverse events and clinical outcomes. We included 155 patients (53 patients [23 once daily, 30 at least twice daily] in RELEASE and 102 patients [54 once daily, 48 at least twice daily] in SENIOR). Between trials, we found similar recruitment rates (1.32 and 1.26 patients/month/ICU) and reasons for trial exclusion, high consent and protocol adherence rates (> 92%), infrequent crossovers, and few adverse events. Although underpowered, at least twice daily screening was associated with a nonsignificantly faster time to successful extubation and more successful extubations but significantly increased use of noninvasive ventilation in both trials combined.Similar recruitment and consent rates, few adverse events, and comparable outcomes in younger and older patients support conduct of a single large trial in North American ICUs assessing the net clinical benefits associated with more frequent screening.